Can you suggest an anime with an adult male MC, that had a difficult past?

[watcher]

Okay, so, it'd be great if the MC had a difficult past and also still living a difficult life. I don't want childish characters (if that's possible) or children as MCs. 
Thank you in advance!

***I'm new to this forum, so excuse me if I've made a mistake about anything.

[Ohayotaku]

Some suggestions off the top of my head: Cowboy Bebop; Megalobox; Hakata  Tonkatsu Ramens. Maybe Monster (the MCs life has a lot of promise at the beginning, but that ends very quickly). I’ll also mention Welcome to the NHK, though in that case a lot of the hardship is his doing, and it’s more of a dark comedy.

Edited July 7, 2019 by Ohiotaku

[Seshi]

Afro Samurai, Samurai X OVAs, and Trigun.

Edited to add: Berserk, and Bananafish 

Edited July 8, 2019 by Seshi

[Serge heartless]

Baki from Baki the grappler maybe had the hardest time growing up. Father didn't care about him at all. People don't like him cause they can't beat him in fights. All he's known his whole life is to be the best.  I can't think of any other anime character thats a harder child hood. 

 

[LostEnoki]

Akira is an assumption, but the characters are in a gang so they’re life took a wrong turn somewhere.

Baki the Grappler, but not the newer one. That one was kinda bad.

Mirai Nikki (Future Diary). He’s already bullied, and now he has to deal with Yuno Gasai. Shivers

Koe no Katachi (A Silent Voice) because both main characters are an emotional disaster.

Kids on the Slope isn’t that bad, but Kaoru’s family wasn’t that great, and some of the kids weren’t that friendly to him either, especially because he played piano.

Miss Hokusai was sad because she was always overshadowed by her dad as an artist. Even though she was amazing, she was constantly put down for her art.

Serial Experiments Lain. Lain’s friend dies, and she finds out life is a lie. Any more than that and it’s a spoiler.

Shikioriori touches on three people that all have messy lives.

[Mazino]

91 Days and Gansta. (the latter one will most likely not continue due the studio going bankrupt - unless another studio picks it up which is pretty unlikely)